Re: Octarch of the Old Empire. Its a good theory, except for your inclusion of Elyria. This is clearly a Valyrian settlement (AWOIAF). However Hazdahn No and Ghozai are Ghiscari, bringing the number to 9 (Bhorash is probably Valyrian in origin).

I may have made a mistake with Elyria, but the wiki does note that Hizdahr zo Loraq has kin and political influence there, so…./shrug.

I did mention Vaes Diaf. 

And Ghozai probably wasn’t one of the Octarchy, because it was destroyed during the Doom.